package com.summer.netty;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;


@Sharable //⇽---　标示一个Channel- Handler可以被多个Channel安全地共享
public class EchoServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        ByteBuf in = (ByteBuf) msg;
        System.out.println("Server received: " + in.toString(CharsetUtil.UTF_8));     //⇽---  将消息记录到控制台       

        ctx.write(in); //⇽---　将接收到的消息写给发送者，而不冲刷出站消息

    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);   //⇽---　将未决消息冲刷到远程节点，并且关闭该Channel
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx,Throwable cause) {
        cause.printStackTrace();     //⇽---  打印异常栈跟踪
        ctx.close();    //⇽---　关闭该Channel
    }
}